Slack adjuster for railway brakes



R. w. JOY

SLACK ADJUSTER FOR RAILWAY BRAKES May 5, 1931.

Filed; May 12, 1928 Patented May 5, 1931 l Fries :ROBERT '/Y.' 'JOY, j OF BROOKLYN, 'NEW'. 4YGRLK, ASSGGR TO AMERICAN CAR 'AND- FOUNDRY GOlIl/IPANTZ,` OF NEW STGR-K, N. Y., Vil. CORPORATIN `O1`1-NEW TERSEY snack inmersa non narnia/AY BRAKns f Application filed May 12,

lFhis invention relates to railway brakes and moreparticularly to railway brakes oit the clasptypein whichV there is a series of connected levers ateach side'of the truck, and 5 it is an object of this invention to p rovidezuiV improvedslack adjuster for railway brakes oit the class described" which will beoperated upon brake applicationand release to maintain the brake shoes atthe proper distance from the .car wheels by shifting vthe connec-V Y tion of abrake lever to the rodsconnecting that brake lever te the other brake lever of a pair of levers `fora wheel. It is also an object of'this invention to" provide a slack adjuster ofthe type described which will be positive in its operation until the maximum adji'istm'ent has been'made and which will thereupon cease to operate and prevent j amming or breaking or' the adjusting mechaj juster shown at theleft in-Fig. 1, the section beine taken as on the 1iin-e 2 2 of Fior. 3' te b 9 Fig. 3 is a horizontal section of the structure shown in Fig; 2," the parts being shown as adjusted for newbrake shoes;

F iOs. 4 5 and Gare vertical sections taken t: 9 Y on the lines 4--47 5-`5 and 6-6, respectively,

of Fig. 2; v

Fig-7 is a view partly in plan and partly inhorizontal section showing `the parts of the slack adjuster when shiftedto the positionof maximum adjustment; l

trigger shown detached; Fig. 9 is a side elevation, drawn 4to a-larger scale and showing the application of the's'lack adjuster tothe brakelever 'at the rightoI Fig.1;andf W Fig. 10 lis an end elevation of the structure shown in Fig. 9. I y

In the drawings the slack adjuster is shown applied to a four wheel truck provided with a clasp brake arrangement comprising brake serial-n0. 277,159. 'j l i heads 1' carrying shoes adapted to bear on oppcsitesides or" the wheels and supported by brake hangers 2 pivotally mounted on the truckframe 3. At oneend of the truck is a "live lever 4 pivotally As upp ortedvintermediate vits ends asat 5I and having its upper end connected through suitable brakerigging to the brake cylinder and moved in the direction(v indicated kby the arrow "to apply the brake `shoes to the wheels.

The lower end of lever 4 1s connected by ulcrum 4E5 to the center. of a brake beam 1 0', which, at its endsQ-is connected 'tov the Ylower ends of brake Vlevers Vl2. The "brake levers 12A are connected Vintermediate i their ends tothe adjacentbrake heads 1 and have their upper ends connected through slack adjusters 14 to pairs of spaced tension rods 16.

rlhe other ends of the pairs oftension rods i 16 are 'connected to theupper ends of levers 18 ,which are connected intermediate their ends to the Vadjacent brake heads 1 and have their lower Aends* connectechby compression rods 20 tothe lower ends of brake levers 22.

The brake leversl 22 are connected intermediate theirends'to the iadjacent' brake heads l1 and haveA their upper ends connectedv to the ends of vpairs of spaced tension rods 24; The

. yother ends oit the pairs or ytension rods 24 are 'connected through slack adjusters 26 tothe upper, ends ofbrakelevers 28."v The brake levers 428 are connected intermediate their ends to theadjacent brake heads 1 and have their lower 4ends connected to beams which are. connected byflinks jl21to the truck rame. v

The slack adjuster 14 comprises a casing )34 attachedto the reds l16 by'bolts 36 and a in@V e is a perspective viw of 'thelick Caf-Sing 38 Sildably moundm the rods 16 a' f c by. means of outwardly `projecting guide brake lever 12 and on which is mounted a v.yoke 447 the arms of the'yoke 44 engaging the pin 42 on opposite sides of the lever 12. VAs shown in Fig. 3', the pin 42 is inserted from one side, the insertion of the pin being limited by av reduction of one of the bearing openings, and is retained in position by one of the rods 16.

Piv-otally mounted on the pin 42 is a bellcrank lever 46 having an arm 48 which eX- tends alongside of the brake lever 12 and is provided with an opening 50 in which the head of a pin 52 carried by the brake lever 12 engages, the opening 50 being of greater diameter than the pin 52 and providing for a limited movement of tie pin 52 before the pin operates the bell-crank lever 46. The other arm 54 of the bell-crank 46 engages with a movable rack 56 and reciprocates the rack 56 as the pin 52 operates the bell-crank lever 46. The rack 56 engages with a wheel 58 rotatably mounted on a frictiondrum 66 formed as part of an adjusting screw 62. The wheel 58 has, adjacent the friction drum 60, communicating recesses 64 formed with curved outer surfaces 66 which are eccentric to the surface of the drinn 60. Mounted in the recesses 64 between the wheel 58 and the drum 60 are rollers 68 of less diameter than the widest portions of the recesses and of greater diameter than the narrower portions of the recesses, an arrangement which permits of the wheel 58 and rollers 68 rotating freely on the drum 60 when moved in one direction while binding on the drum 60 and causinT the drum 60 and adjusting screw 62 to rotate therewith when moved in the other direction.

Besides the friction drum portion 60, the adjusting screw comprises a reduced inner end portion 70 which engages in an opening in the yoke 44, a collar Z2 pinned to the outer end and a threaded portion Z4 which extends substantially,7 from the drum 60 to the collar 72 and the length of which determines the permissible adjustment of theupper end of brake lever 12. Surrounding the threaded portion .74 is a two-part nut comprising the parts 7 6 and 77, which have cylindrical outer surfaces engaging correspondingly shaped surfaces in an opening in the casing 34 but which are kept from rotating therein by a lock trigger 8 mounted in alined slots in the parts 76 and 77 and having a head 8O which is normally kept in engagement in a slot 82 by a spring 84 mounted in a recess in the nut part 77 and acting on a lug 86 on the lock trigger 78. To prevent shifting of the adjusting screw 62, exceptupon operation of the bell-crank 46, a spring friction plate 88 is mounted on the end portion 70 of the adjusting screw 62 between the yoke 44 and the drum 60 so that it bears upon both the drum 60 and the yoke 44.

Vahile the operation of the slack adjuster 26 is generally the same as that of slack adjuster 14, the difference in lever conditions at the two ends of the truck necessitates a modification in the manner of operating the bell-crank lever and a difference in the direction of movement of some of the parts. In the case of slack adjuster 26, to one of the adjacent brake hangers 2 is secured a bracket 90 carrying a pin 92 which engages in an elongated opening 94 in the depending arm 48 of the bell-crank 46', the opening 94 being wide enough to provide the saine lost motion is provided by the opening` 50. lilith this arrangement, as the arm 54 of slack adjuster 14 moves downwardly upon an application of the brakes, the arm 54 of slack adjuster 26 moves upwardly. This results in a movement in opposite directions of. the 'acks and wheels of the two slack adjusters, but this difference is corrected by changing the position and direction of taper of the recesses in the wheel of slack adjuster 26 so that in both cases the wheels and rollers move freely on the friction drums if the bell cranks are operated Vduring an application of the brakes biit bind on 'the drums and rotate the drums and adthe bell-cranks are operatj a release of the brakes.

An application of the brakes will cause the bottom of lever 12 to move to the right in F ig. 1, pivoting about its upper end until the brake shoe bears against the wheel, after which the lever 12 will pivot about its connection with the brake head 1 and the upper end of the lever 12 will be moved to the left in Fig. 1, carrying with it the tension rods 16 and operating the rest of the lever system to apply the other brake shoes to the wheels. The change in the angular relation of lever 12 to rods 16 causes a movement of the pin 52 in opening 50 of the bell-crank lever 46 and the change in angular relation increases with the wear of the brake shoes; the n'iovement of pin 52 in opening 5() increases until eventually the movement of the pin 52 is sufficient to operate the bell-crank in both application and release of the brakes. As shown, operation of the bell-crank 46 during the application by the pin 52 causes the arm 48 to be moved to the right in F ig. 2 and the arm 54 downwardly. rllhe arm 54 moves the rack 56 downwardly and rotates the wheel 58 and rollers 68 about the drum 60, the recesses being arranged so that the rollers 68 do not bin d when the wheel is operated by the rack moving downwardly. Upon a release of the brakes, operation of the bell-crank 46 by the pin 52 moves the arm 48 to the left in Fig. 2 and arm 54 upwardly. The arm 54 moves therack 56 upwardly and starts to rotate the wheel 58 about the drum 60 in the oppo site direction; but this movement of the wheel 58 causes the rollers 68 to bind between the curved surfaces 66 and the drum 60 and rotate the drum 6() and adjusting screw 62 with the wheel 58. As the two-part nut is nor mally held against rotation in the casing 34, rotation of the adjusting screw 62 causes the screw to be advanced in the two-part nut and carrying with it the yoke 44 which,

through its engagement with the pin 42,

moves the casing 38 and the upper end ,of

brake lever 12 along the rods 16, thus sliertening the distance between the upper ends of brake levers 12 and 18 and bringing their brake shoes closer to the wheel.

The operation just described is repeated as the wear of the shoes continues until the movement of the adjusting screw 62 in the two-part nutbrings the collar72 into engagement with the outer end of Vthe lock trigger f 78, whereupon further movement of the adj usting screw 62 in the two-part nut will disengage the head 80 of lock trigger 7 8 irom 15 the slot 82 in casing 34 permitting the twopart nut to revolve in the casing 34 and preventing any further movement of the adjusting screw 62 in the two-part nut. To retract the adjusting screw 62 and casing 38, the two-part nut is rotated by means of a wrench applied to the flat surfaces provided on the part 76, the lock trigger 7 8 being held to prevent engagement in the slot 82 assoon as the collar 72 is moved from the outer end of the lock trigger 78.

As the operation of slack adjuster 26 is the same as the operation of slack adjuster 14, eX- cept for the diierences particularly pointed out, it is believed that the operation of slack 30 adjuster 26 will be clear from the description given. It is t-o be understood that the drawings herein are for illustrative purposes only and that various changes in the forni and proportions of the device may be made within the scope of the appended claims without departing from the spirit of the invention.

What is claimed is i 1. In a brake, a brake lever, rods operatively connected to said lever and means interposed between said rods and lever for shifting the eti'ective connection of said rods and lever comprising a casing connected to said rods, a second casing movably mounted on said rods and connected to said lever, an adjusting screw mounted in said first casing and operative to shift said second casing and means operative upon relative movements of said rods and lever to operate said adjusting screw.

2. In a brake, a brake lever, rods operatively connected to said lever and means interposed between said rodsv and lever for shitting the effective connection ot said rods and lever comprising a casing connected to said rods, a second casing slidably mounted on said rods and connected to said lever, an adjusting screw mounted in said iirst casing and operative to shift said second casing, and means mounted in said second casing and operative upon relative movement of said rods and lever to operate said adjusting screw.

3. In a brake, a brake lever, rods operatively connected to said lever and means interposed between said rods and brake lever 65 for shifting the eiifective connection of said interposed between said rods and lever for shifting the effective connection of said rods and lever comprising a casing connectedto said rods, a second casing slidably mounted onw said rods and connected to said lever, an d adjusting screw mounted in said first casing s55V and operative to shift said second casing, means operative upon a predetermined movement of said rods and lever to operate said adjusting screw and means operated by said adjusting screw to limit the'movement of edf said second casing by said adjusting screw.

5. Ina brake, abralre lever, rods operatively connected to said lever' and means interposedy between said rods and lever for shifting the edective connection of said rods `1 and lever comprising a casing connected to said rods, a two-part nut mounted in said Casing, a loclr trigger preventing rotation of Said nut in said casing, a second casing slidably mounted on said rods and connected to said lever, an adjusting screw mounted in said two-part nut and operative to shift said second casing and means operative upon rel-V ative movement of said rods and lever to operate said adjustingscrew, said adjusting screw being operative upon a predetermined movement thereof to operate said lock trigger to release said two-part nut to limit the shifting of said second casing.

6. In a brake, a brake lever, rods operatively connected to said brake lever and means interposed between said rods and, brake lever for shifting the effective connection of said rods and brake lever comprising a casing connected to said rods, a second casf ing slidably mounted on said rods, a pinl mounted in said second casing and en` gaging said brake lever, an adjusting screw mounted in said first casing and operatively connected to said pin, a bell-crank lever mounted on said pin and operatively connected to said brake lever, a rack reciprocated by said bell-crank lever and a wheel mounted on said adjusting screw and operated by said rack to rotate said adjusting screw and shiftvsaid second casing.

7. In a brake, a brake lever, rods operatively connected to said lever and means interposed between said rods and lever for shifting the effective connection of said rods and lever comprising a casing secured to said rods, a second casing slidably mounted on said rods, an adjusting` screw mounted in said first casing and operative to shift said second casing, means mounted in said second casing and operated by said brake lever to operate said adjusting screw and a. brake for said adj usting screw in said second casing.

8. In a brake, a. brake lever, rods operativelyY connected to the upper end of said lever and means interposed between said rods and lever to shift the effective connection of said rods and lever comprising a casingsecured to said rods, a second casingslidably mounted on said rods and connected to the upper end of said lever, an adjusting screw mounted in said iirst casing and operatively connected to said casing` and bralie lever and means operated upon movement o1 said brake lever to rotate said adjusting screw and shift said second casing` and the upper end o1"- said brake lever with respect to said rods.

9. In a brake, a brake lever, a tension rod, and a slack adjuster interposed between said tension rodI and brake lever and operated b v said brake lever.v

l0. In a brake, a brake lever, av tension rod, and a slack adjuster interposed between said tension rod and brake lever and operated by said brake lever for varying the effective length of said rod upon operation or the brake.

ll. In a brake, a brake lever, a tension rod, and a slack adjuster interposed between said tension red and brake lever and operated by said brake lever for shifting the el'ective connection of said rod and lever.

l2. In a brake, a brake lever, a brake rod, casings connected to said lever and rod and means operative upon relative movement of ,l aid lever and rod to cause relative movement of said casings to var7 the effective connection of said lever and rod.

13. In a brake, a brake lever, a brake rod,

' casings connected to said lever and rod, means to cause relative movement of said casings to vary the eilective connnection of said lever and rod and means operative upon relative movement of said rod and lever to operate said casing moving means.

In witness whereof I have hereunto set my hand.

ROBERT W. JOY. 

